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Your computer cannot read some or all files on CDs or DVDs that were recorded through the use of the Optical Storage Technology Association (OSTA) Universal Disk Format (UDF) file system standard. Symptoms may include:

The disc is not recognized at all and shows up as empty.

Error messages such as "The file or directory is corrupt and unreadable" appear when you try to access files in Windows Explorer.

Some portions of a DVD-video may not function correctly (note that this may also be because of a problem with the DVD video data or the player software, which is outside the scope of this article).

The version of Microsoft Windows that you are using may not support the UDF version that is used on the disc. Most DVD-ROM/video that contain UDF 1.02 CD or DVD R/RW content that was recorded by "drag-and-drop" software will contain UDF 1.5 or later. Windows XP supports UDF 1.02, 1.5, and 2.01.

The recording software that was used to create the disc may have generated structures on the disc that are not valid (not compliant with the standard), which cannot be read by other UDF readers (such as those built into Windows XP). Some "pressed" DVD-ROMs and DVD-videos also contain errors. (See "References" for a UDF-validation tool that can search for errors on the disc.)

Certain "drag-and-drop" recording programs (for example, the Adaptec/Roxio DirectCD program) allow the use of "compression" when you format discs. Compression is not a part of the OSTA UDF standard, and discs that have compression may not be readable by any UDF reader except readers from that software vendor.

For CD-Rs and DVD-Rs, the disc may be "open." Before you can use the disc in computers that do not have the recording software installed, the disc must be made ready ("closed" or "finalized").

The drive cannot read the media type. For example, not all DVD-ROM drives can read DVD-Rs. Many DVD-ROM drives cannot read DVD-RAMs. There is no way to work around this problem other than replacing the drive or using a different media type.

The disc may be a "bad burn." Some recorder/media brand/reader combinations are incompatible.

Make sure that you have the latest Windows service pack applied. Search the Microsoft Web site for any hotfixes that may have been issued for the Microsoft UDFS file system driver after the latest service pack release.

If the disc is a commercial title and the version of Windows you are using contains UDF support, contact the title vendor.

If your Windows version supports the UDF version on the disc and the disc is a 'bridge disc' that contains ISO9660 or Joliet (for example DVD-ROM discs are typically bridge discs), try to open Windows Media Player while the disc is in the drive. Windows Media Player sends a particular type of file system request that can sometimes cause the disc to become visible through the CDFS file system.

If you are recording the disc yourself, make sure that the following conditions are true:

You have the latest updates for your recording software.

You have not selected compression (if available) in the recording software.

The disc has been prepared for use in other computers (if applicable) before you remove the disc from the recorder.

The UDF version you are writing is supported in the version of Windows you are using to read the disc.

If the disc is not a commercial title, if you are not recording it yourself, or if it was recorded some time ago and the content is unavailable elsewhere, follow these steps:

Contact the vendor of the recording software used to write the disc. Some vendors make available free UDF reading software (see the "More Information" section below) which supports any non-standard extensions to UDF used by the vendor (for example, compression) and also ignore disc format errors caused by bugs in the vendor's writing package.

If the version of Windows that you are using has no UDF support or does not support the version you need, use the same workaround as the case earlier.

Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information.

The third-party products that are discussed in this article are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.